sick blue spot stingray-HELP

[nfherman]

i have a 24" blue spot stingray with a 10" disc. I have had him for almost 2 years and he has been great. About two weeks ago he stopped eating and I noticed a pimple on his back, in the middle of the disc, getting progressively larger. Yesterday the pimple opened exposing his flesh. He is still not eating and his stinger looks like it is decaying. His eyes are starting to cloud over. I have a 40gal breeder tank set up as a quarantine.
Is there any med for a ray?
What can I do??

Thanks